$8\times8\,\,Ka$ -Band Dual-Polarized Array Antenna Based on Gap Waveguide Technology

Abstract

This paper describes an 8×8 fully-metallic highefficiency dual-polarized array antenna working at Ka-band, based on Gap Waveguide concept. The radiating element is a circular aperture backed by two stacked cylindrical cavities, which are fed orthogonally to achieve a dual-polarized performance. Both feeding layers consist of a gap waveguide corporate network to reach all the cavities backing each radiating element. Cavities are naturally integrated within the bed of nails hosting grooves and ridges for guiding EM field, leading to a low-profile dualpolarized array in Ka-band. Experimental results present good agreement with simulations. Measured radiation patterns agree well with simulation and the antenna provides an average gain over 27 dBi within its operating bandwidth (29.5 to 31 GHz).

Dual Circularly Polarized Aperture Array Antenna in Gap Waveguide for High-Efficiency Ka-Band Satellite Communications

“…This has been done on purpose. Measurements in [8] revealed that the phase difference in broadside direction between V-Pol and H-Pol field components was of −140 • at the central frequency (30.25 GHz). However right-hand CP (RHCP) would need −90 • phase difference instead.…”

“…The first of these pieces hosts a novel Riblet-type coupler implemented in GW. The remaining three pieces that make up the antenna are, in ascending order, the feeding, coupling and radiation layers, which were previously presented in [8].…”

“…This hybrid directional coupler has been designed to operate in Ka band from 29.5 GHz to 31 GHz. This range corresponds to the working band of the antenna to which the hybrid will be connected [8], so a wider frequency bandwidth is not sought. Fig.…”

“…Once the coupler is designed in Gap Waveguide, the next step is connecting it to the dual linearly-polarized antenna [8] from its back. However, this antenna from a previous project was not initially designed to be connected to any additional parts.…”

“…Here the development initiated in [8] is culminated. The objective has been to achieve the dual-circular-polarization performance from a dual linearly-polarized antenna.…”